This invention relates to article transferring means which are employed in the handling of open mouth containers, such as glass jars, during the loading and unloading of boxes. More particularly, the present invention is directed to an element of such article transferring means which grips a container during handling.
The prior art discloses various means for transferring containers, and each includes a type of apparatus for gripping a container during handling. While one type of apparatus grips the exterior surface of a container, such as the apparatus shown in U.S. Pat. No. 3,086,805, such a form of engagement cannot be employed in handling wide mouth containers. This is because the size of the spaces in boxes closely approximates the size of the mouths of such containers, and, consequently, the physical dimensions of external gripping apparatus preclude proper alignment of containers required for loading and unloading.
In order to handle wide mouth containers, the prior art discloses another type of apparatus which grips the interior surface of a container. One such apparatus is shown in U.S. Pat. No. 2,818,987 and includes a rubber cup supported by a rod together with a plate which is slid downwardly on the rods to compress the rubber cup such that the walls of the rubber cup bulge outwardly thereby frictionally gripping the interior surface of a container. Because the rod is rigid, however, there is no sidewise flexibility, and the gripping apparatus occasionally hangs up on the lip of a misaligned container and crushes it or knocks it over. Furthermore, the structure that is disclosed in this patent is mechanically complex since there are many moving parts for actuating the gripping apparatus. Additionally, there is no means for adjusting the gripping apparatus for handling containers with different mouth sizes.
U.S. Pat. No. 3,075,800 discloses an apparatus for gripping the interior surface of a container which includes a piston and cylinder, the cylinder being connected to an air manifold through a rubber hose which mounts the gripping apparatus to the container transferring means. The piston has camming surfaces contacting gripper fingers. When air is introduced into the cylinder, the piston cams the gripper fingers apart to frictionally grip the interior surface of a container, and upon removal of the air a spring and a rubber diaphragm return the piston to the top of the cylinder and reclose the gripper fingers. Since the gripping apparatus in this patent is mounted by the rubber hose, the rubber hose flexes sidewise to eliminate to some extent hang up on the lip of a misaligned container. Nevertheless, the rigid gripper fingers on occasion hang up on the lip of a misaligned container. Additionally, there is no means by which the gripping apparatus can be adjusted for handling containers of different mouth sizes.